Olfaction is the sensory system which, in mammals, provides detection and identification of airborne substances. It operates efficiently because it is extraordinarily sensitive over an extended range of odorant concentrations and because it provides broad discrimination among a great variety of substances even at low concentrations. These features make the olfactory system unique in its roles of sensing and identifying chemical compounds. However, the mechanisms whereby detection and discrimination of odorants are achieved in the olfactory epithelium are unknown. The study of these mechanisms is the long-range goal of this research project. The membrane electrical properties of freshly dissociated receptor neurons and support cells from mouse olfactory epithelia will be studied with the patch-clamp technique. This method allows both single-channel currrents and whole-cell currents to be resolved and examined under a variety of conditions in vitro. The sensitivity of the technique is commensurate with that reported for the olfactory system, allowing interactions of single molecules to be detected if they cause channel activation. Questions about the physiological role of the interdependencies between odor substances and membrane conductance in the olfactory receptor cells will be addressed to study odor detection and discrimination.